Add more examples to run on CI

[Radonirinaunimi]

Triggered by this comment I think it'd be indeed good to run the Python examples on the CI. Indeed, while running all of the examples, the Python ones broke which I fixed in #310. More Python examples should also be added.

[cschwan]

The C, C++ and Fortran APIs are run, tested and code coverage is generated here: https://github.com/NNPDF/pineappl/blob/master/.github/workflows/capi.yaml. For the Python interface we should have more examples, run and test them in the CI, of course.

[Radonirinaunimi]

The C, C++ and Fortran APIs are run, tested and code coverage is generated here: https://github.com/NNPDF/pineappl/blob/master/.github/workflows/capi.yaml. For the Python interface we should have more examples, run and test them in the CI, of course.

Ah, yes! Then it is just about adding more Python examples and also run them on the CI.

EDIT: Updated the description.

[cschwan]

Then I believe this is a duplicate of #108.

[Radonirinaunimi]

I agree, I will implement this there.